Fuel cell system controlled in accordance with drive condition of fuel cell

ABSTRACT

A fuel cell system supplies a reacting solution from a liquid storage section to a reaction section to generate a reacting gas. A gas storage section stores the reacting gas and supplies it to a solid polymer membrane fuel cell which generates electricity using the reacting gas as fuel. The reacting solution is supplied from the liquid storage section to the reaction section when the pressure in the liquid storage section is higher than the pressure in the reaction section and the supply of reacting solution is stopped when the pressure in the liquid storage section is lower than the pressure in the reaction section. In this manner, the supply volume of the reacting solution is controlled in accordance with the driving state of the fuel cell.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage application of copendingInternational Application No. PCT/JP2004/002077, filed Feb. 23, 2004,claiming priority dates of Feb. 24, 2003 and Feb. 10, 2004, andpublished in a non-English language.

FIELD OF THE INVENTION

The present invention relates to a fuel cell system for supplyinghydrogen and oxygen so as to drive a solid polymer type fuel cell.

BACKGROUND ART

Recently, importance has been attached to solve energy and environmentalproblems. Therefore, it is demanded to provide an electric power sourceof high energy density, the emission matter of which is clean. The fuelcell is a generator, the energy density of which is several times ashigh as that of the conventional battery. The energy efficiency of thefuel cell is high. Further, the exhaust gas discharged from the fuelcell contains no nitrogen oxide and sulfur oxide. Alternatively, theexhaust gas discharged from the fuel cell seldom contains nitrogen oxideand sulfur oxide. Accordingly, it is said that the fuel cell is a veryeffective device which meets the demand for an electric power sourcedevice of the next generation. Especially, the solid polymer type fuelcell has a good starting characteristic because it can be driven even atlow temperatures of not higher than 100° C. Therefore, the solid polymertype fuel cell has been actively developed so that it can be used as astationary dispersion type power source, an automobile power source anda power source incorporated into a portable device.

The high molecular type fuel cell is a device operated in such a mannerthat the oxidization of hydrogen on the anode and the reduction ofoxygen on the cathode are electrochemically conducted at the same time,and an electrical output can be obtained by an electric current takenout from a potential difference between the anode and cathode in theelectrochemical reaction process. The conventional fuel cell includes: afuel storage section for storing a reactant; a reacting section forreforming the reactant to fuel gas; a fuel supply passage; an anode orcathode for generating electricity by the electrochemical reaction offuel; and an electrolyte for transmitting ions between the anode andcathode.

Examples of the anode side fuel conventionally used are: hydrogen,alcohol such as methanol or ethanol; ether; and chemical hydride such ascyclohexanol or sodium boron hydride. Except for hydrogen, all the fueldescribed above is used in the form of liquid and transformed intohydrogen gas by are forming device. Concerning the fuel cell, thedeveloper's attention has been focused upon the selection of chemicalsubstance which is effective for taking out hydrogen and suitable fortransporting and storing the fuel. Attention is given to the fueldescribed above because the fuel is assumed to be effective for the fuelcell.

The reactant on the cathode side is an oxidant. The typical oxidant isoxygen. However, a peroxide such as hydrogen peroxide is used in somecases.

In order to drive a device, which consumes electric power, such as anelectrical appliance, a portable device and an automobile by a fuelcell, it is necessary for the fuel cell to output electric power, theintensity of which corresponds to a load of the device which consumeselectric power. An output of the fuel cell is a factor determined by avolume of the reacting gas to be supplied to the electrode such ashydrogen gas or oxygen gas. Accordingly, when an extremely large volumeof the reacting gas exists in the periphery of the electrode, an outputof the fuel cell can be changed responding to the load given to the fuelcell. From this viewpoint, when the reacting gas is appropriatelysupplied to the electrode before hydrogen and oxygen existing in theperiphery of the electrode are used up, it is possible for the fuel cellto be operated responding to the load of the device which consumeselectric power.

In this case, in order to supply a necessary volume of the reacting gas,it is necessary to obtain the necessary volume of the reacting gas fromthe above fuel and oxidant. Accordingly, an appropriate volume of fuelmust be supplied from the fuel storage section to the reacting section.Further, an appropriate volume of oxidant must be supplied to thereacting section.

When the fuel, oxidant and reacting gas are supplied, it is conventionalto use a pump or blower. The volumes to be supplied are controlledaccording to the output of the fuel cell and the load of the devicewhich consumes electric power. Concerning this matter, for example,refer to Non-patent Document 1.

Non-patent Document 1: “Technical Tendency of Portable Type Fuel Cell”by Masahiro Ichimura, pages 2 to 4 and FIG. 3 in NTT Building TechnologyInstitute 2003

However, in any of the anode and the cathode, it is difficult to controlthe volumes of fuel and reacting gas to be supplied to the electrode. Inorder to control the volumes of fuel and reacting gas, it is necessaryto input energy, which is used for controlling, from the outside or thefuel cell itself into the control system. Accordingly, since energy isconsumed for controlling as described above, the effective output of thefuel cell is decreased.

Further, in the case where hydrogen is used as the fuel on the anodeside, when hydrogen is taken out by reforming the reactant, it isnecessary to control a volume of the generated hydrogen according to avolume of hydrogen used on the anode. In order to control the volume ofthe generated hydrogen, it is necessary to control a reactiontemperature and a volume of fuel to be supplied. Therefore, it isnecessary to attach a temperature control system such as a heater,temperature sensor and controller to the reacting section and theelectrode. Further, it is necessary to attach a valve and controller forcontrolling the volume of fuel to be supplied. Accordingly, energy isfurther consumed by the above control mechanism for controlling thereaction. Therefore, the effective output of the fuel cell is decreased.

At the same time, especially, in the case of a fuel cell applied to asmall electronic device, a space, in which fuel is to be accommodated,is decreased by the volume in which the above system is arranged.Accordingly, the volume of this system is very disadvantageous in thevolume energy density. By the volume of this system, the volume energydensity of this fuel cell is lowered as compared with the volume energydensity of the conventional battery.

In the case where the system of controlling a volume of the generatedhydrogen is not provided, the inner pressure in the fuel cell is raisedby the hydrogen generated exceeding a volume of hydrogen correspondingto an electric current to be outputted. In this case, the generatedhydrogen cross-leaks to the cathode side through the solid highmolecular electrolyte film, and an output of the cathode is lowered.

When the hydrogen leaks out as described above, it is impossible toeffectively use the hydrogen. Therefore, the energy density is lowered.

Problems caused on the anode are described above, however, the sameproblems are also caused on the cathode. In the case where oxygen isgenerated from the oxidant and the thus generated oxygen is supplied tothe cathode, it is necessary to control the volume of the generatedoxygen according to the volume of the used oxygen. Energy is consumedfor this control. Further, in order to arrange the controllingmechanism, the volume energy density is decreased.

It is an object of the present invention to decrease energy necessaryfor supplying appropriate volumes of fuel and oxidant to an electrode ofa fuel cell so as to decrease a volume of the control mechanism forcontrolling a volume of the supply and also decrease a volume of thecontrol mechanism for controlling a volume of the reaction. It isanother object of the present invention to solve the above problems inthe conventional art by providing a small fuel cell system, which isused for a portable device, characterized in that the energy density isadvantageously high, the size of the fuel cell is small, the fuel cellcan be safely operated and the fuel utilizing efficiency is high.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention provide afuel cell system comprising: a liquid storage section for storing areacting solution; a reacting section for generating reacting gas fromthe reacting solution supplied from the liquid storage section; a gasstorage section for storing the reacting gas supplied from the reactingsection; a fuel cell having an electrode which is arranged being joinedto a solid high molecular electrolyte film, generating electricity whilethe reacting gas supplied from the gas storage section is being used asfuel; and a reacting solution supply volume adjusting means forsupplying the reacting solution from the liquid storage section to thereacting section in the case where the pressure in the liquid storagesection is higher than the pressure in the reacting section and forstopping the supply of the reacting solution in the case where thepressure in the liquid storage section is lower than the pressure in thereacting section.

The action conducted by the above structure will be explained below.When the reacting gas is generated in the reacting section, the innerpressure in the reacting section and the gas storage section is raised.In this case, the reacting solution is not supplied to the reactingsection by the reacting solution supply adjusting means. On the otherhand, when the reacting gas is consumed by the fuel cell, the innerpressure in the reacting section and the gas storage section is lowered.In this case, the reacting solution is supplied to the reacting sectionby the reacting solution supply adjusting means.

A fuel cell system further comprises a pressure adjusting device forgiving pressure to the liquid storage section in the case where theinner pressure of the liquid storage section is lowered by the supply ofthe reacting solution.

Due to the foregoing, even when the reacting solution is supplied fromthe liquid storage section to the reacting section, the inner pressurein the liquid storage section is quickly adjusted by the pressureadjusting device to a constant pressure.

The reacting solution supply volume adjusting means includes a checkdevice which is arranged in a liquid supply passage for supplying thereacting gas from the liquid storage section to the reacting section,and the check device prevents the reacting solution from flowingbackward or prevents the reacting gas from flowing in.

The action conducted in the above structure will be explained below.When the reacting gas is generated in the reacting section, the innerpressure in the reacting section and the gas storage section is raised.However, since the check device prevents the reacting gas from flowinginto the liquid storage section, the inner pressure in the liquidstorage section is not raised. Further, the inner pressure in the liquidstorage section can be maintained constant by the pressure adjustingdevice. In this case, since the inner pressure in the reacting sectionis higher than that in the liquid storage section, supplying thereacting solution can be stopped. On the other hand, when the reactinggas is consumed by the fuel cell, the inner pressure in the reactingsection and the gas storage section is lowered. Since the check devicedoes not obstruct a flow of the reacting solution from the liquidstorage section to the reacting section, when the inner pressure in thereacting section is decreased to be lower than the inner pressure of theliquid storage section, the reacting solution is supplied to thereacting section by the differential pressure.

A volume of the reacting solution to be supplied is determined by theoutput of the fuel cell. That is, the rate of consuming the reacting gasis changed according to the output of the fuel cell. When the rate ofconsuming the reacting gas is high, a period of time from the generationof the reacting gas to the supply of the reacting solution is shortened,and the reacting solution is supplied at a short time interval. On thecontrary, when the rate of consuming the reacting gas is low, thefrequency of supplying the reacting solution is reduced.

As described above, according to this structure, a volume of supplyingthe reacting solution can be controlled according to the state ofdriving the fuel cell without directly detecting the electric poweroutputted from the fuel cell. That is, no electrical control signals areused for the reacting solution supply control. Therefore, it becomeunnecessary to conduct electrical processing and provide electricalparts relating to electrical control. Accordingly, the energyconsumption can be reduced, and further the number of parts can bedecreased. Since the reacting solution can be supplied according to thestate of driving the fuel cell, the fuel utilizing efficiency, which isa ratio of the fuel consumption to the supply of the reacting gas, canbe increased.

In this case, the reacting gas is fuel, which is used for the fuel cell,such as hydrogen and oxygen, and oxidant. Examples of the combination ofthe reacting solution with the substance arranged in the reactingsection are described as follows but not limited to the following. Onthe anode side, they are at least one of the groups including a group ofalcohol such as methanol or ethanol, a group of ether, a group ofchemical hydride such as metal hydride complex compound represented bycyclohexane and sodium boron hydride and a group of metals such asaluminum, magnesium, zinc, iron, nickel and tin, and at least one of thecatalysts and the accelerator used for effectively extracting hydrogen.Either the former or the latter may be used in the reacting solution. Itis preferable that the substance capable of being held as an aqueoussolution or liquid is used as the reacting solution. An example of thecatalyst and accelerator is one substance included in the group ofplatinum, gold, copper, nickel and iron with respect to a group ofalcohol, a group of ether and a group of organic chemical hydride suchas cyclohexane. With respect to inorganic chemical hydride, an exampleof the catalyst and accelerator is one metal in the group of platinum,gold, copper, nickel, iron, titanium and zirconium, and its salt andinorganic acid such as sulfuric acid or citric acid. With respect toaluminum and other metals, it is inorganic acid or an aqueous solutioncontaining hydroxide ions.

On the cathode side, they are at least one of peroxides represented byhydrogen peroxide, and a catalyst used for effectively extracting oxygenfrom the above substance, for example, manganese dioxide.

A fuel cell system is characterized in that the check device opens andcloses a liquid supply passage.

This structure is preferably composed in such a manner that when thepressure in the liquid storage section is higher than the pressure inthe reacting section, the reacting solution is supplied from the liquidstorage section to the reacting section and when the pressure in theliquid storage section is lower than the pressure in the reactingsection, the supply of reacting solution is stopped.

Due to the foregoing, it is possible to eliminate the energy consumptionrelating to the driving of the check device. That is, no electric poweris required for supplying the reacting solution. As a result, it becomespossible to enhance the output density and the energy density of thefuel cell system.

A fuel cell system is characterized in that the check device is a firstcheck valve to obstruct a flow of substance from the reacting section tothe liquid storage section.

Due to the foregoing, a small check device can be simply manufactured ata low manufacturing cost. Concerning the check valve, it is preferableto use a check valve of the type in which the check valve body is movedaccording to the direction of the substance flowing in the valve,because no electric power is consumed. Concerning the fuel cell used fora portable device, it is preferable that an intermediate chamber is notprovided in the fuel cell, because the volume of the fuel cell can bereduced. Further, it is preferable that no ventilation hole is provided,because the reacting gas seldom leaks out from the fuel cell.

Concerning the structure of the check device different from the above,the check device is a first movable wall interposed between the liquidstorage section and the reacting section, and when the pressure in thereacting section is raised by generation of the reacting gas, themovable wall is moved by a force generated by the pressure in thereacting section so that the liquid supply passage can be closed, andwhen the pressure in the reacting section is lowered by the consumptionof the reacting gas, the movable wall is moved so that the liquid supplypassage can be opened.

This structure is operated by a difference in pressure between thereacting section and the liquid storage section. A change in pressure inthe reacting section is caused by the output of the fuel cell. Since thepressure in the liquid storage section is constant, the difference inpressure between the reacting section and the liquid storage sectionreflects a state of the operation of the fuel cell. Due to theforegoing, by the state of the operation of the fuel cell, a volume ofthe reacting solution can be automatically controlled without theconsumption of electric power.

The fuel cell system is characterized in that the pressure adjustingdevice has a port from which an external substance is taken in, and theexternal substance is supplied from the port into the liquid storagesection in one direction.

The action of the above structure will be explained below. When theinner pressure in the liquid storage section is lowered corresponding toa volume of supply of the reacting solution, a difference in pressure isgenerated between the liquid storage section and the outside of the fuelcell system. However, since the external substance flows into the liquidstorage section according to the generation of the difference inpressure, the pressure in the liquid storage section is adjusted andmade to be the same as the external pressure. Accordingly, the innerpressure in the liquid storage section can be maintained constant.Therefore, at the time of consuming the reacting gas, the pressure inthe reacting section can be decreased lower than the inner pressure inthe liquid storage section. Accordingly, it is possible to make acircumstance in which the reacting solution is supplied.

The external substance is not particularly limited to a specificsubstance. It is preferable that the external substance is theatmosphere, the water or the reacting solution. In the case of theatmosphere, the pressure in the liquid storage section can be adjustedto the atmospheric pressure, and the structure of the external substancetaking port can be made to be a pipe or hole having such a structurethat the substance in the liquid storage section does not flow outsidethe fuel cell. In the case of the water or the reacting solution, wateror the reacting solution is arranged coming into contact with theexternal substance taking port. In this case, the water or the reactingsolution flowing into the liquid storage section can be used for thereacting gas generating reaction. Therefore, the capacity can beenhanced.

Due to the foregoing, in the case where the reacting solution is movedfrom the liquid storage section, the pressure in the liquid storagesection can be made constant by introducing the external substance, thevolume of which corresponds to the volume of the moved reactingsolution. As a result, it becomes possible to repeatedly supply thereacting solution from the liquid storage section to the reactingsection.

Further, the fuel cell system is characterized in that the pressureadjusting device has a second check valve to obstruct a flow of thesubstance from the liquid storage section to the outside of the fuelcell.

Due to the foregoing, it becomes possible to provide a structure inwhich no electric power is consumed for the object of maintaining theinner pressure of the liquid storage section constant. Further, itbecomes possible to prevent a decrease in the volume of liquid caused bythe evaporation and flow-out of the liquid from the liquid storagesection. Further, it is possible to simply manufacture a check device,the volume of which is small, at a low manufacturing cost.

Further, the fuel cell system is characterized in that the pressureadjusting device has a pump or fan to supply liquid or gas from theoutside of the fuel cell.

Due to the foregoing, the pressure in the liquid storage section can beadjusted. However, it is necessary to consume electric power for drivinga pump or fan. However, since a movement of the reacting solution forobtaining a volume of generation of the reacting gas used to stop themovement of the reacting solution is very small. Accordingly, a drive ofthe pump or fan is small. Therefore, the electric power consumption issmall.

In this connection, in order to control to drive the pump or fan, amethod is provided in which the pressure in the liquid storage sectionis detected and a difference in pressure between the thus detectedpressure and the initial pressure is detected and the pump or fan isdriven until the difference in pressure is eliminated.

When the pump or fan is controlled so that the pressure in the liquidstorage section can be higher than a predetermined pressure, a volume ofsupply of the reacting solution is controlled so that the inner pressurein the reacting section and the gas storage section can be balanced tothe inner pressure in the liquid storage section. As a result, a volumeof generation of the reacting gas is increased. Accordingly, thepressure in the reacting section and the gas storage section can beraised high. Consequently, it becomes possible to enhance an output ofthe fuel cell of the present structure.

The fuel cell system is characterized in that a portion of the liquidstorage section has a second movable wall operated by a force given fromthe outside of the liquid storage section which is generated by theatmospheric pressure, the driving force of a motor, the magnetic forceor the force generated by a spring, and a volume of the liquid storagesection is changed by the second movable wall so that the inner pressureof the liquid storage section can be maintained constant.

Due to the foregoing, when the reacting solution is moved from theliquid storage section to the reacting section, the second movable wallis moved in a direction so that the volume of the liquid storage sectioncan be reduced. Accordingly, the inner pressure in the liquid storagesection can be made constant without exchanging a substance with theoutside of the fuel cell. Therefore, the aged deterioration of thereacting solution in the liquid storage section can be suppressed.

In the method of driving the second movable wall, a motor, magnet orspring is used. In the case of using a magnetic force, a magnet isarranged on the second movable wall and the stationary portion in theperiphery of the movable wall, so that the second wall can be pushed bya repulsion of the magnet. In the case of using a spring, in the samemanner as that described above, the spring is arranged, while connectingthe second movable wall with the stationary portion in the periphery ofthe movable wall, so that the second movable wall can be pushed. Due tothe foregoing, the pressure in the liquid storage section can beincreased without using electric power.

In the case of conducting drive control with a motor, a method isprovided in which the pressure in the liquid storage section is detectedand a difference between the pressure in the liquid storage section andthe initial pressure is detected and the motor is operated until thedifference in pressure is eliminated. In the case of using a magneticforce, when an electromagnet is used, it is possible to change amagnetic force by adjusting an electric current flowing in theelectromagnet. Therefore, while the electric current is being adjusted,the second movable wall can be moved by generating the magnetic forceuntil the difference in pressure is eliminated in the same manner asthat described above. Due to the foregoing, the pressure in the liquidstorage section can be increased, and an output of the fuel cell can beenhanced.

The fuel cell system is characterized in that a face of the secondmovable wall opposing to the inner face of the liquid storage section iscommunicated with the atmosphere.

Due to the foregoing, a drive force given on the movable wall facebecomes a difference in pressure between the inner pressure in theliquid storage section and the atmospheric pressure. Accordingly, evenwhen the reacting solution flows out from the liquid storage section andthe inner pressure in the liquid storage section is lowered, the innerpressure in the liquid storage section can be returned to apredetermined value without using electric power.

The fuel cell system is characterized in that the second movable wall iscomposed of a rubber-like elastic body. Therefore, when the reactingsolution is moved, the second movable wall is deflected, so that theinner pressure in the liquid storage section can be maintained constant.

Due to the foregoing, the inner pressure in the liquid storage sectioncan be maintained constant without using movable parts. Therefore, itbecomes possible to eliminate a leakage of the reacting solution from asliding portion between the liquid storage section and the movableparts. Accordingly, a volume of the use of the reacting solution can beincreased.

The fuel cell system is characterized in that the pressure adjustingdevice is a gas passage, in which the reacting gas flows, providedbetween the liquid storage section and the reacting section.

Due to the foregoing, when the reacting gas flows into the liquidstorage section, the inner pressure in the liquid storage section can bemade to be the same as the pressure of the reacting gas which has flowedinto the liquid storage section. As a result, in the case where thereacting gas supplied to the gas storage section is consumed and theinner pressure in the gas storage section and the reacting section islowered, a difference in pressure is generated between the liquidstorage section and the reacting section by the pressure of the reactinggas which has flowed into the liquid storage section, and the reactingsolution can be supplied to the reacting section.

The fuel cell system is characterized in that the gas passage has apressure reducing device, and the pressure reducing device reduces thepressure of the reacting gas, which flows from the reacting section tothe liquid storage section, to a predetermined pressure.

Due to the foregoing, the inner pressure in the liquid storage sectionbecomes a setting inner pressure of the pressure reducing device, andthe inner pressure in the reacting section can be made higher than thesetting pressure. When a regulator is used for the pressure reducingdevice, the inner pressure in the liquid storage section can be made tobe a predetermined pressure without consuming electric power. Since nosubstance flows into the fuel cell system and no load is given to thefuel cell system from the outside, it is possible to tightly close thefuel cell system. Therefore, it is possible to build a stable device.

The fuel cell system is characterized in that the pipe diameter of theliquid supply passage is larger than the pipe diameter of the gaspassage.

Due to the foregoing, the resistance at the time when the reacting gaspasses in the gas passage is higher than the resistance at the time whenthe reacting solution passes in the passage. Accordingly, a flow of thereacting solution from the liquid storage section into the reactingsection is much easier than a flow of the reacting gas. Accordingly,when the pressure in the liquid storage section becomes higher than thepressure in the reacting section, the reacting solution can be moved.

The fuel cell system is characterized in that the liquid supply passageis hydrophilic. In order to give the hydrophilicity, for example, TiO2is dispersed and coated.

Due to the foregoing, the passage gets wet with the reacting solution.Therefore, it is possible to reduce a friction loss caused in the flowof the reacting solution in the passage. Accordingly, concerning thesubstance flow conducted between the reacting section and the liquidstorage section, the reacting solution can flow more easily than thereacting gas. Accordingly, it can be said that the reacting solution caneasily flow from the liquid storage section to the reacting section whenthe inner pressure in the reacting section is reduced.

When the passage gets wet with the reacting solution, it becomesdifficult for the gas to enter the passage. Accordingly, when thereacting solution is moved from the liquid storage section to thereacting section, no gas enters the passage. Accordingly, a movement ofthe reacting solution can not be obstructed.

The fuel cell system is characterized in that the gas passage ishydrophobic. In order to give hydrophobicity, for example, a waterrepellent agent such as PTFE may be coated.

Due to the foregoing, it become difficult for the reacting solution toenter the gas passage. Accordingly, in the case where the reacting gasis generated and the pressure in the reacting section becomes higherthan the pressure in the liquid storage section, the reacting gas is notobstructed from flowing into the liquid storage section. Accordingly, itcan be said that even when the inner pressure in the liquid storagesection is lowered in the case where the reacting solution is moved fromthe liquid storage section to the reacting section, the inner pressurein the liquid storage section can be quickly raised.

Further, the fuel cell system is characterized in that the liquid supplypassage and gas supply passage are respectively a film or a porousmember through which liquid is transmitted.

Due to the foregoing, the passage and the gas passage can be easilymade.

The present invention provides a fuel cell system comprising: a liquidstorage section for storing a reacting solution; a reacting section forgenerating reacting gas from the reacting solution supplied from theliquid storage section; a gas storage section for storing the reactinggas supplied from the reacting section; a fuel cell having an electrodewhich is arranged being joined to a solid high molecular electrolytefilm, generating electricity while the reacting gas supplied from thegas storage section is being used as fuel; and a liquid feeding devicefor feeding the reacting solution from the liquid storage section to thereacting section, wherein the liquid feeding device prevents thereacting solution from flowing backward from the reacting section to theliquid storage section, and when the inner pressure in the gas storagesection is lowered according to the consumption of the reacting gas, theliquid feeding device moves the reacting solution from the liquidstorage section to the reacting section.

Due to the foregoing, the reacting solution is moved by the innerpressure in the gas storage section. That is, irrespective of the innerpressure in the reacting section, when a volume of the reacting gas inthe periphery of the fuel cell is lowered, the reacting solution is sentto the reacting section, so that the reacting gas can be generated.Especially, in the case where a subsidiary product is generated in thereacting section, in order to prevent the movement of the subsidiaryproduct to the gas storage section, it is preferable that a reacting gastransmitting film is arranged between the reacting section and the gasstorage section. However, in this case, it is impossible for the innerpressure in the gas storage section to instantaneously cope with theinner pressure in the reacting section. However, in the presentstructure, even when a volume of the reacting gas in the gas storagesection is decreased, since the reacting gas can be generated bysupplying the reacting solution from the liquid storage section to thereacting section, the reacting gas can be quickly supplied to the gasstorage section.

The fuel cell system is characterized in that the liquid feeding sectionincludes: an accommodating section for accommodating the reactingsolution which moves from the liquid storage section to the reactingsection; and an accommodating section moving mechanism for moving theaccommodating section, and the accommodating section is a containerhaving an opening section and a shut-off section, when the openingsection moves to the reacting section and the shut-off section moves tothe liquid storage section according to a decrease in the inner pressurein the gas storage section, the communication between the accommodatingsection and the liquid storage section is shut off and the accommodatingsection and the reacting section are communicated with each other, andwhen the opening section moves to the liquid storage section and theshut-off section moves to the reacting section according to an increasein the inner pressure in the gas storage section, the accommodatingsection and the liquid storage section are communicated with each otherand the communication between the accommodating section and the reactingsection is shut off.

Due to the foregoing, when the inner pressure in the gas storage sectionis decreased to be lower than the inner pressure in the liquid storagesection, the reacting solution accommodated in the accommodating sectionis supplied from the liquid storage section to the reacting section. Thereacting solution accommodated in the accommodating section does notflow backward to the liquid storage section at this time.

At this time, to be in more detail, the accommodating section movingmechanism includes a third movable wall and a pressurizing means, thethird movable wall is arranged facing the gas storage section, thepressurizing means is arranged on a face opposing to the gas storagesection of the third movable wall, and when the inner pressure in thegas storage section is lower than the pressure of the pressurizingmeans, the third movable wall is moved to the gas storage section sideand the accommodating section is moved in the direction coming intocontact with the reacting section, and when the inner pressure in thegas storage section is higher than the pressure of the pressurizingmeans, the third movable wall is moved to the pressurizing means sideand the accommodating section is moved in the direction coming intocontact with the liquid storage section.

The action of the present structure will be explained below. In the casewhere the inner pressure in the gas storage section is higher than thepressure generated by the pressurizing means, the third movable wall ismoved to the pressurizing means side. Being linked with this movement ofthe third movable wall, the opening portion of the accommodating sectionis moved to the liquid storage section, and the accommodating sectionand the liquid storage section are connected with each other.Accordingly, the reacting solution can be accommodated in theaccommodating section. On the other hand, in the case where the innerpressure in the gas storage section is lower than the pressure generatedby the pressurizing means, the third movable wall is moved to the gasstorage section side. Being linked with this movement of the thirdmovable wall, the opening portion of the accommodating section is movedto the reacting section, and the reacting section and the accommodatingsection are connected with each other. Accordingly, the reactingsolution can be moved to the reacting section.

In this case, it is preferable to arrange a capillary tube, film, porousmember or cloth at the circulation port between the accommodatingsection and the reacting section. Due to the foregoing, it becomespossible to facilitate a movement of the reacting solution from theaccommodating section to the reacting section by the surface tension.

Due to the foregoing, the reacting solution can be moved by a decreasein the pressure in the gas storage section without consuming electricpower.

The fuel cell system is characterized in that the pressurizing meansincludes a motor, a magnet, a spring or an elastic body.

In this case, it is possible to consider that the pressurizing means isformed into a cylindrical shape and a plunger provided in the cylinderis made to be the third movable wall. When a face opposing to the gasstorage section of the third movable wall is pushed by the above parts,the third movable wall can be moved being balanced with the innerpressure in the gas storage section.

The fuel cell system is characterized in that the pressure of thepressurizing means is the atmospheric pressure.

In this case, it is possible to consider that the pressurizing means isformed into a cylindrical shape and a plunger provided in the cylinderis made to be the third movable wall and one end portion of the cylinderis connected to the inside of the gas storage section and the other endportion of the cylinder is connected to the inside of the liquid storagesection. When a face opposing to the gas storage section of the thirdmovable wall is communicated with the atmosphere, it is possible tobuild a pressurizing means capable of raising the pressure in the gasstorage section higher than the atmospheric pressure.

The fuel cell system is characterized in that the pressure of thepressurizing means is the pressure in the liquid storage section.

In this case, it is possible to consider that the pressurizing means isformed into a cylindrical shape and a plunger provided in the cylinderis made to be the third movable wall and one end portion of the cylinderis connected to the inside of the gas storage section and the other endportion of the cylinder is connected to the inside of the liquid storagesection. When the pressure given to the face opposing to the gas storagesection of the third movable wall is made to be the inner pressure inthe liquid storage section, it is possible to build a pressurizing meanscapable of raising the inner pressure in the gas storage section higherthan the inner pressure in the liquid storage section.

A fuel cell system comprises: a liquid storage section for storing areacting solution; a reacting section for generating reacting gas fromthe reacting solution supplied from the liquid storage section; a gasstorage section for storing the reacting gas supplied from the reactingsection; a fuel cell having an electrode which is arranged being joinedto a solid high molecular electrolyte film, generating electricity whilethe reacting gas supplied from the gas storage section is beingelectrochemically reacted and used as fuel; and a bulkhead forpartitioning the reacting section and the reacting solution, wherein atleast one of the bulkhead and the reacting section is movable andcapable of being moved in a direction so that a contact area of thereacting section with the reacting solution can be changed.

Due to the foregoing, the generation and stoppage of the reacting gascan be conducted. According to the output of the fuel cell, a decreasingrate of the inner pressure of the gas storage section is changed.According to this change, a movement conducted by the moving means ischanged. As a result, a contact area of the reacting solution with thereacting member can be made variable. Accordingly, a volume of thegenerated reacting gas can be controlled according to the output of thefuel cell. That is, in the case where a large volume of the reacting gasis required by the electrode, a contact area of the reacting solutionwith the reacting section is increased, so that the volume of thegenerated reacting gas can be increased.

In this case, a substance, which is capable of generating the reactinggas when it is contacted with the reacting solution, is arranged so thatit can be used as the reacting member. That is, when the reactingsolution is an aqueous solution of the metal hydride complex compound,its catalyst is arranged in the reacting section. On the contrary, whenthe reacting section is the metal hydride complex compound or itsaqueous solution, the reacting solution is made to be an aqueoussolution of the catalyst. In the case where hydrogen is generated byusing the reacting solution of alcohol represented by methanol, ether ororganic chemical hydride represented by cyclohexane, it is necessary toheat. Therefore, when a heater is arranged in the reacting member andthe catalyst is provided, hydrogen can be generated.

Further, the fuel cell system is characterized as follows. The bulkheadis arranged on a face on the reacting solution side of the reactingsection, the bulkhead moving means has a pressurizing device forpressurizing the bulkhead in a direction so that the reacting sectionand the reacting solution can be contacted with each other, the bulkheadis moved by a difference in pressure between the pressurizing means andthe reacting gas, and a moving direction of the bulkhead is changed by achange in the pressure caused by the generation and consumption of thereacting gas.

Furthermore, the fuel cell system is characterized as follows. Thebulkhead is arranged on a face on the reacting solution side of thereacting section, the reacting section moving means has a pressurizingdevice for pressurizing the reacting section in a direction so that thereacting section and the reacting solution can be contacted with eachother, the reacting section is moved by a difference in pressure betweenthe pressure in the pressurizing means and the pressure in the reactinggas, and a moving direction of the reacting section is changed by achange in the pressure caused by the generation and consumption of thereacting gas.

Due to the above structure, when the pressure of the reacting gas israised, the reacting section is shut off by the bulkhead. Therefore, thereacting section is not contacted with the reacting solution and the gasgeneration is stopped.

The pressurizing device may be composed of an elastic body made ofrubber or spring. Alternatively, the pressurizing device may be composedof a magnet, a motor or a device in which an electrostatic phenomenon ora piezoelectric phenomenon is used. Alternatively, it is possible toadopt such a structure that a portion of a wall face of a closedcontainer, in which gas or liquid is accommodated, is made to be movableand the container is attached to the bulkhead or the reacting member. Itis preferable that a member not consuming electric power is used.However, the frequency of operating the movable portion is not so high.Therefore, even when electric power is consumed, the power consumptionis small.

The fuel cell system is characterized in that a through-hole, throughwhich the reacting section is contacted with the reacting solution, isformed in a portion of the bulkhead.

Due to the above structure, the reacting solution can be supplied to thereacting section through the through-hole.

A fuel cell system having an electrode, which is arranged being joinedto a solid high molecular electrolyte film, generating electricity whilethe reacting gas is being electrochemically reacted, comprises: astorage tank for storing the reacting gas; a gas section into which thereacting gas flows and from which the reacting gas is sent out to theelectrode; a gas tube for supplying the reacting gas from the storagetank to the gas section; and a pressure reducing section, which isarranged in the gas tube and used for adjusting the pressure of thereacting gas sent out to the gas section, wherein a reduction of theinner pressure in the gas section at the time of generating electricityby the fuel cell is caused only by the reaction conducted in the fuelcell.

Due to the foregoing, the reacting gas flows into the gas sectionaccording to the balance between the inner pressure of the gas sectionand the output pressure of the pressure reducing means. Accordingly, inthe fuel cell, when the reacting gas is consumed and the inner pressurein the gas section is decreased, the reacting gas can be supplied to thegas section.

As explained above, in order to solve the above problems, the presentinvention provides a fuel cell system comprising: a liquid storagesection for storing a reacting solution; a reacting section forgenerating reacting gas from the reacting solution supplied from theliquid storage section; a gas storage section for storing the reactinggas supplied from the reacting section; a fuel cell having an electrodewhich is arranged being joined to a solid high molecular electrolytefilm, generating electricity while the reacting gas supplied from thegas storage section is being used as fuel; and a reacting solutionsupply volume adjusting means for supplying the reacting solution fromthe liquid storage section to the reacting section in the case where thepressure in the liquid storage section is higher than the pressure inthe reacting section and for stopping the supply of the reactingsolution in the case where the pressure in the liquid storage section islower than the pressure in the reacting section.

As described above, a volume of supplying the reacting solution can becontrolled in accordance with the state of driving the fuel cell withoutdirectly detecting an output electric power of the fuel cell. That is,since no electrical control signals are used for controlling a volume ofthe reacting solution, it is unnecessary to conduct electricalprocessing relating to the control. Therefore, it is unnecessary toprovide electronic parts. Accordingly, the energy consumption can bereduced, and the number of part scan be decreased. Further, since thereacting solution can be supplied in accordance with the state ofdriving the fuel cell, the fuel utilizing efficiency, which is a ratioof the volume of the supplied reacting gas to the volume of the consumedgas, can be enhanced.

A fuel cell system comprises: a liquid storage section for storing areacting solution; a reacting section for generating reacting gas fromthe reacting solution supplied from the liquid storage section; a gasstorage section for storing the reacting gas supplied from the reactingsection; a fuel cell having an electrode which is arranged being joinedto a solid high molecular electrolyte film, generating electricity whilethe reacting gas supplied from the gas storage section is being used asfuel; and a liquid feeding device for feeding the reacting solution fromthe liquid storage section to the reacting section, wherein the liquidfeeding device prevents the reacting solution from flowing backward fromthe reacting section to the liquid storage section, and when the innerpressure in the gas storage section is lowered according to theconsumption of the reacting gas, the liquid feeding device moves thereacting solution from the liquid storage section to the reactingsection.

Due to the foregoing, the reacting solution is moved by the innerpressure in the gas storage section. That is, when a volume of thereacting gas in the periphery of the fuel cell is reduced, the reactingsolution can be sent to the reacting section and the reacting gas can begenerated irrespective of the inner pressure in the reacting section.Especially, in the case of generating a subsidiary product in thereacting section, in order to prevent the subsidiary product from movinginto the gas storage section, it is preferable to arrange a reacting gastransmitting film between the reacting section and the gas storagesection. However, in this case, it is impossible for the inner pressurein the gas storage section to instantaneously cope with a change in theinner pressure in the reacting section. However, according to thepresent structure, even when a volume of the reacting gas in the gasstorage section is decreased, the reacting solution can be supplied fromthe liquid storage section to the reacting section and the reacting gascan be generated. Therefore, the reacting gas can be quickly supplied tothe gas storage section.

A fuel cell system comprises: a liquid storage section for storing areacting solution; a reacting section for generating reacting gas fromthe reacting solution supplied from the liquid storage section; a gasstorage section for storing the reacting gas supplied from the reactingsection; a fuel cell having an electrode which is arranged being joinedto a solid high molecular electrolyte film, generating electricity whilethe reacting gas supplied from the gas storage section is beingelectrochemically reacted and used as fuel; and a bulkhead forpartitioning the reacting section and the reacting solution, wherein atleast one of the bulkhead and the reacting section is movable andcapable of being moved in a direction so that a contact area of thereacting section with the reacting solution can be changed.

Due to the foregoing, the generation and stoppage of the reacting gascan be conducted. According to the output of the fuel cell, thedecreasing ratio of the inner pressure in the gas storage section ischanged. According to this change in the decreasing ratio, a movementconducted by the moving means is changed. As a result, a contact area ofthe reacting solution with the reacting member can be made variable.Accordingly, a volume of the generated gas corresponding to the outputof the fuel cell can be controlled.

A fuel cell system having an electrode, which is arranged being joinedto a solid high molecular electrolyte film, generating electricity whilethe reacting gas is being electrochemically reacted, comprises: astorage tank for storing the reacting gas; a gas section into which thereacting gas flows and from which the reacting gas is sent out to theelectrode; a gas tube for supplying the reacting gas from the storagetank to the gas section; and a pressure reducing section, which isarranged in the gas tube and used for adjusting the pressure of thereacting gas sent out to the gas section, wherein a reduction of theinner pressure in the gas section at the time of generating electricityby the fuel cell is caused only by the reaction conducted in the fuelcell.

Due to the foregoing, the reacting gas flows into the gas sectionaccording to the balance between the inner pressure in the gas sectionand the output pressure of the pressure reducing means. Accordingly, inthe fuel cell, when the reacting gas is consumed and the inner pressurein the gas section is decreased, the reacting gas can be supplied to thegas section.

Due to the above structure, energy, which is necessary for supplyingappropriate volumes of fuel and oxidant to the electrode of the fuelcell, can be reduced, and the control mechanism for controlling a volumeof supply and the control mechanism for controlling an reaction can bemade small in volume. Accordingly, it becomes possible to provide asmall and safe fuel cell, the fuel utilizing efficiency of which ishigh, which is advantageous from the viewpoint of energy density.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an arrangement view showing a fuel cell system of the presentinvention.

FIG. 2 is a flow chart showing a control method of controlling a volumeof hydrogen to be supplied of the present invention.

FIG. 3 is an arrangement view showing a case in which a movable wall isused for a check device of a fuel cell system of the present invention.

FIG. 4 is an arrangement view showing a case in which a movable wall isused for a check device of a fuel cell system of the present invention.

FIG. 5 is an arrangement view showing a case in which a movable wall isused for a check device of a fuel cell system of the present invention.

FIG. 6 is an arrangement view showing a case in which a check valve isattached to a pressure control device of a liquid storage section of afuel cell system of the present invention.

FIG. 7 is an arrangement view showing a case in which a movable wall isused for a pressure adjusting device of a liquid storage section of afuel cell system of the present invention.

FIG. 8 is an arrangement view showing a case in which a movable wall isused for a pressure adjusting device of a liquid storage section of afuel cell system of the present invention.

FIG. 9 is an arrangement view showing a case in which a magnet is usedfor a pressure adjusting device of a liquid storage section of a fuelcell system of the present invention.

FIG. 10 is an arrangement view showing a case in which a motor is usedfor a pressure adjusting device of a liquid storage section of a fuelcell system of the present invention.

FIG. 11 is an arrangement view showing a case in which a spring is usedfor a pressure adjusting device of a liquid storage section of a fuelcell system of the present invention.

FIG. 12 is an arrangement view showing a case in which a gas passage isused for a pressure adjusting device of a liquid storage section of afuel cell system of the present invention.

FIG. 13 is an arrangement view showing a case in which a gas passage isused for a pressure adjusting device of a liquid storage section of afuel cell system of the present invention.

FIG. 14 is an arrangement view showing a case in which a volume of thereacting solution is controlled by a change in pressure in a gas storagesection of a fuel cell system of the present invention.

FIG. 15 is an arrangement view showing a case in which a volume of thereacting solution is controlled by a change in pressure in a gas storagesection of a fuel cell system of the present invention.

FIG. 16 is an arrangement view showing a case in which a volume of thegenerated gas is controlled when an area of a reacting portion of a fuelcell system of the present invention is made variable.

FIG. 17 is an arrangement view showing a case in which a volume of thegenerated gas is controlled when an area of a reacting portion of a fuelcell system of the present invention is made variable.

FIG. 18 is an arrangement view showing a case in which a gas storagetank is used for a fuel cell system of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be explained in detail on the basis ofembodiments.

Embodiment 1

FIG. 1 is an arrangement view showing a fuel cell system of the presentinvention. The fuel cell system mainly includes a liquid storage section1, a reacting section (reaction section) 2, a gas storage section 3 anda fuel cell. The liquid storage section 1 is a portion for storing areacting solution to generate hydrogen. The reacting solution issupplied to the reacting section 2 through the liquid supply passage 13.The reacting section 2 is provided with a reactant capable of generatinghydrogen when it comes into contact with the reacting solution. When thereacting solution is supplied to the reacting section 2, hydrogen isgenerated in the reacting section 2. The thus generated hydrogen issupplied to the gas storage section 3. In the gas storage section 3, thehydrogen supplied from the reacting section 2 is temporarily stored. Thefuel cell includes an anode 4 a, a solid high molecular electrolyte film4 b and a cathode 4 c. Hydrogen in the gas storage section 3 iselectrochemically oxidized by the anode 4 a and electricity isgenerated.

The fuel cell is a so-called solid polymer type fuel cell. To be in moredetail, the fuel cell includes: an anode 4 a for electrochemicallyoxidizing hydrogen; a cathode 4 c for electrochemically reducing oxygen;and a solid high molecular electrolyte film 4 b interposed between theanode 4 a and the cathode 4 c. In this case, since the gas storagesection 3 is tightly closed by the solid high molecular electrolyte film4 b, the hydrogen stored in the gas storage section 3 does not leakoutside but is consumed by the anode 4 a.

The liquid storage section 1 includes: a pressure adjusting device 20;and a liquid supply passage 13 for supplying a reacting solution to thereacting section 2. The first check valve 11 is arranged in the liquidsupply passage 13. The pressure adjusting device 20 is a device formaintaining the pressure in the liquid storage section 1 constant. Bythe action of the pressure adjusting device 20, even when the innerpressure in the liquid storage section 1 is temporarily decreased, itcan be returned to the initial pressure. A factor of decreasing theinner pressure in the liquid storage section 1 is the supply of thereacting solution to the reacting section 2 through the liquid supplypassage 13. In this connection, by the action of the first check valve11, there is no possibility that the hydrogen generated in the reactingsection 2 flows into the liquid storage section 1.

The control method of controlling a volume of hydrogen to be supplied ofthe present invention is shown in the flow chart in FIG. 2.

According to the flow chart in FIG. 2, first of all, when the reactingsolution is supplied to the reacting section 2, hydrogen is generated inthe reacting section 2. Therefore, the pressure in the reacting section2 is raised, and the hydrogen is supplied to the gas storage section 3.Further, the hydrogen is supplied from the gas storage section 3 to theanode 4 a. At this time, the hydrogen can be prevented from flowing intothe liquid storage section 1 by the action of the first check valve 13.Accordingly, the pressure in the liquid storage section 1 is maintainedconstant by the pressure adjusting device 20. Due to the foregoing, thepressure in the reacting section 2 is raised. However, since thepressure in the liquid storage section 1 is not changed, the pressure inthe liquid storage section 1 is lower than the pressure in the reactingsection 2, and the supply of the reacting solution from the liquidstorage section 1 to the reacting section 2 is stopped.

Next, when the hydrogen is consumed by the generation of electricity,the inner pressure in the gas storage section 3 and the reacting section2 is lowered. When the inner pressure in the reacting section 2 isdecreased to be lower than the inner pressure in the liquid storagesection 1, in order to correct the differential pressure, the reactingsolution is supplied from the liquid storage section 1 to the reactingsection 2. The same operation is repeatedly conducted hereinafter.

In this embodiment, a fuel cell, the specific structure of which isdescribed below, was used. A film electrode joining body was made inwhich a catalyst layer composed of a carbon layer born by platinum wascoated on both sides of the solid high molecular electrolyte film 4 c.This film electrode joining body was interposed between pieces of carboncloth. A member having cavities for storing hydrogen inside was attachedat a position, which covered the anode 4 a, so that the inside hydrogencould not leak outside. In this way, the gas storage section 3 wasformed. Acrylic containers were used for the liquid storage section 1and there acting section 2. The liquid storage section 1 accommodated areacting solution of a 4 cc aqueous solution of 25 wt % sodium boronhydride, and the reacting section 2 accommodated an acid aqueoussolution of pH3 for generating hydrogen from sodium boron hydride. Theliquid supply passage 13 was provided between the liquid storage section1 and the reacting section 2. A check valve was attached to the liquidsupply passage 13. The reacting section 2 and the gas storage section 3were connected to each other so that gas could be communicated betweenthem. A volume of the accumulation of generated hydrogen was 2.4 L underthe above condition. Electric power 5.7 Ahr can be theoretically takenout in the above circumstances.

In the above fuel cell system, it was possible to continue generatingelectricity for 10.9 hours at the constant current 0.5 A. The efficiencyof electric current generation with respect to the theoretical value was96%. As a result of the experiment in which the electric current wasvariously changed, the electric current generation efficiency was 96%.This is the result obtained when the present fuel cell systemautomatically changed a volume of hydrogen generation without consumingelectric power. Therefore, it was made clear that the fuel cell systemof the present invention can automatically cope with various cases ofthe electric power output.

The first comparative example was executed as follows. Theaforementioned aqueous solution was mixed so as to generate hydrogen.When the thus generated hydrogen was sent to the fuel cell, electricpower was generated at the constant current 0.5 A for 50 minutes.However, substantially simultaneously when the hydrogen generatingreaction was finished, the generation of electric power was stopped. Inthis case, the electric current generating efficiency was 7%. The reasonwhy the electric current generating efficiency was low was that thegenerated hydrogen leaked outside the fuel cell and the volume ofhydrogen to generate electricity was insufficient.

The second comparative example was executed as follows. An ultra lowvolume of an aqueous solution of sodium boron hydride was continuouslysent to the reacting section 2 by a pump. Electric power consumption ofthe pump was 100 mW. The generation of electric power by the fuel cellcontinued for 9.5 hours, and the electric current generating efficiencywas 84%. However, since electric power was consumed by the pump, only50% of the theoretical electric power was practically used. As a resultof the experiment of generating electricity by the fuel cell in whichthe electric current was variously changed, the electric currentgenerating efficiency was 74%. The net electric power, in which theelectric power consumption of the pump was considered, was 40% of thetheoretical value. The cause of the decrease in the electric currentgenerating efficiency is described as follows. Since a volume of thedischarged reacting solution was very small, it was difficult tostabilize the volume of the discharged reacting solution. Further, itwas difficult to operate the pump in accordance with the output of thefuel cell. It was confirmed again that the effective output of the fuelcell was lowered because the pump consumed electric power.

In this connection, in this embodiment, the generation of hydrogen wasdescribed. However, this description can be also applied to thegeneration of oxygen. That is, when manganese dioxide is arranged in thereacting section 2 and hydrogen peroxide is used for the reactingsolution, it is possible to control the generation of oxygen. In thiscase, the gas storage section 3 becomes a temporary storage portion forstoring oxygen so that oxygen can be sent to the cathode 4 c in thepower generating section 4.

Embodiment 2

FIG. 3 is a view showing a structure in which a movable wall is used forthe check device of the fuel cell system of the present invention. FIG.3( a) shows a state in which the reacting solution is stopped in itsmovement, and FIG. 3( b) shows a state in which reacting, solution ismoved. The constitution and function of the liquid storage section 1,the reacting section 2, the gas storage section 3 and the electric powergenerating section are the same as those of Embodiment 1.

The structure of the present embodiment is different from that of theembodiment described above as follows. The first movable wall 12 wasused for the check structure arranged in the liquid supply passage 13.The first movable wall 12 is arranged in a space connected to the liquidsupply passage 13, and the cross-section of the first movable wall 12 islarger than that of the liquid supply passage 13. When the first movablewall 12 is moved to the liquid storage section 1 side, the liquid supplypassage 13 is closed. When the first movable wall 12 is moved to thereacting section 2 side, the liquid supply passage 13 is opened.According to the change in the pressure in the liquid storage section 1and the reacting section 2, this structure is operated as follows.

First, in the case shown in FIG. 3( a) in which the reacting solution isstopped in its movement, the pressure in the reacting section 2 ishigher than the pressure in the liquid storage section 1. Accordingly,the first movable wall 12 is moved to the liquid storage section 1 sidein response to this pressure differential, and the liquid supply passage13 is closed and the movement of the reacting solution is stopped.

Next, in the case shown in FIG. 3( b) in which the reacting solution ismoved, the pressure in the liquid storage section 1 is higher than thepressure in the reacting section 2. Accordingly, the first movable wall12 is moved to the reacting section 2 side, and the liquid supplypassage 13 is opened. At the same time, since the pressure in the liquidstorage section 1 is higher than the pressure in the reacting section 2,the reacting solution is supplied to the reacting section 2.

Further, when hydrogen is generated from the reacting solution in thereacting section 2, the above phenomenon is repeatedly conducted.

In this embodiment, an aqueous solution of cobalt chloride was used forthe reacting solution, and while hydrogen was being generated by puttingsodium boron hydride into the reacting section 2, the fuel cell wasoperated. It was confirmed that the aqueous solution of cobalt chloridewas moved to the reacting section 2 according to the operation of thefuel cell, and the fuel cell was continuously operated.

Embodiment 3

FIG. 4 is a view showing a structure in which a movable wall is used forthe check device of the fuel cell system of the present invention. FIG.4( a) shows a state in which the reacting solution is stopped in itsmovement, and FIG. 4( b) shows a state in which the reacting solution ismoved. The constitution and function of the liquid storage section 1,the reacting section 2, the gas storage section 3 and the fuel cell arethe same as those of Embodiment 1.

The structure of the present embodiment is different from that of theabove embodiment as follows. The check valve 11 and the first movablewall 12 were used for the check structure arranged in the liquid supplypassage 13. The check valve 11 is opened in the direction from theliquid storage section 1 to the reacting section 2 and closed in theopposite direction. This structure is operated as follows.

First, in the case shown in FIG. 4( a) in which the reacting solution isstopped in its movement, the pressure in the reacting section 2 ishigher than the pressure in the liquid storage section 1. Accordingly,the check valve 11 and the first movable wall 12 are given a force,however, since the liquid storage section 1 is filled with liquid, themovable wall 12 is not moved.

Next, in the case shown in FIG. 4( b) in which the reacting solution ismoved, since the pressure in the reacting section 2 is lower than thepressure in the liquid storage section 1, a force is given so that thefirst movable wall 12 and the reacting solution in the liquid supplypassage 13 can be moved to the reacting section 2 side. However, sincethe reacting solution can be more easily moved than the first movablewall 12 because of its low friction, the reacting solution is suppliedfrom the liquid storage section 1 through the check valve 11 to thereacting section 2. Accordingly, the first movable wall 12 is moved inthe direction so that a volume of the liquid storage section 1 can bereduced corresponding to the volume of the reacting solution suppliedfrom the liquid storage section 1 to the reacting section 2.

In the same manner as that of Embodiment 2, it was confirmed that anaqueous solution of cobalt chloride was moved to the reacting section 2,and the fuel cell was continuously operated.

Embodiment 4

FIG. 5 is a view showing a structure in which a movable wall is used forthe check device of the fuel cell system of the present invention. FIG.5( a) shows a state in which the reacting solution is stopped in itsmovement, and FIG. 5( b) shows a state in which reacting solution ismoved. The constitution and function of the liquid storage section 1,the reacting section 2, the gas storage section 3 and the fuel cell arethe same as those of Embodiment 1.

The structure of this embodiment is different from that of theembodiment described above as follows. When the first movable wall 12slides in the direction perpendicular to the liquid supply passage 13,the liquid supply passage 13 is opened and closed. In order to move thefirst movable wall 12, the structure is composed as follows. There isprovided a plunger 14, which moves when the plunger is given the innerpressure of the liquid storage section 1 and the reacting section 2,between the liquid storage section 1 and the reacting section 2. Theplunger 14 is attached with a slider 16 a, and the first movable wall 12is attached with a slider 16 b. The gear 15 is arranged so that thesliders 16 a and 16 b can be moved being linked with each other. Whenthe plunger 14 is moved, the slider 16 a rotates the gear 15 inaccordance with the movement of the plunger 14. Accordingly, the slider16 b is slid. As a result, the first movable wall 12 can be moved.

When the pressure in the reacting section 2 is higher than the pressurein the liquid storage section 1, the plunger 14 is moved to the liquidstorage section 1 side, and the first movable wall 12 closes the liquidsupply passage 13 as shown in FIG. 5( a). Accordingly, no reactingsolution is moved.

When the pressure in the reacting section 2 is lower than the pressurein the liquid storage section 1, the plunger 14 is moved to the reactingsection 2 side, and the first movable wall 12 opens the liquid supplypassage 13 as shown in FIG. 5( b). Therefore, the reacting solutionpasses through the liquid supply passage 13 and is supplied to thereacting section 2 by the differential pressure between the liquidstorage section 1 and the reacting section 2.

Accordingly, it was possible to build a fuel cell system in which noelectric power is consumed and a volume of the reacting solution isautomatically adjusted.

Embodiment 5

FIG. 6 is an arrangement view showing a case in which a check valve isattached to the pressure adjusting device of the liquid storage sectionof the fuel cell system of the present invention. The constitution andfunction of the liquid storage section 1, the reacting section 2, thegas storage section 3 and the fuel cell are the same as those ofEmbodiment 1.

In this embodiment, the pressure adjusting device is composed of anexternal substance taking port 21 and a second check valve 27 arrangedat the external substance taking port 21. A reduction in the pressure inthe liquid storage section 1, which is caused when the reacting solutionis supplied from the liquid storage section 1 to the reacting section 2,is suppressed when gas and liquid are taken into the liquid storagesection 1 through the external substance taking port 21 from the outsideof the fuel cell system. Therefore, the inner pressure in the liquidstorage section 1 can be maintained constant.

Specifically, 50 mL of an aqueous solution of sodium hydroxide of 1mol/L is accommodated in the liquid storage section 1, and 5 g of flakesof aluminum are accommodated in the reacting section 2. In thisconnection, when the substances are provided by the quantities describedabove, aluminum is left because all aluminum has not been reacted yet.Therefore, although not shown in the drawing, a container, into whichsodium hydroxide of 1 mol/L is put, is attached to the externalsubstance taking port 21, and when the pressure in the liquid storagesection 1 is decreased, the aqueous solution of sodium hydroxide ismoved to the liquid storage section 1. Due to the foregoing, since anaqueous solution of sodium hydroxide can be continuously replenished tothe liquid storage section 1, all flakes of aluminum can be used forgenerating hydrogen, and the fuel cell continues to generate electricityuntil the hydrogen generating reaction is finished. As described above,according to this structure, it was possible to automatically adjust thepressure in the liquid storage section 1 without using a deviceconsuming electric power. As a result, it was possible to continuouslydrive the fuel cell. Further, it was confirmed that the electric powergenerating time was able to be extended by using the reacting solutionfor the external substance.

Embodiment 6

FIG. 7 is an arrangement view showing a case in which a movable wall isused for the pressure adjusting device of the liquid storage section ofthe fuel cell system of the present invention. The constitution andfunction of the liquid storage section 1, the reacting section 2, thegas storage section 3 and the fuel cell are the same as those ofEmbodiment 1.

In this embodiment, the pressure adjusting device is the second movablewall 22 attached to the liquid storage section 1. The action will bedescribed below. When the reacting solution is moved from the liquidstorage section 1 to the reacting section 2, the inner pressure in theliquid storage section 1 is lowered. Therefore, a differential pressureis generated between the atmospheric pressure and the inner pressure inthe liquid storage section 1. Accordingly, the second movable wall 22 ismoved by the differential pressure to the side on which a volume of theliquid storage section 1 can be decreased. Due to the foregoing, theinner pressure in the liquid storage section 1 can be maintained at theatmospheric pressure thereby suppressing a reduction in the pressure inthe liquid storage section 1 caused when the reacting solution issupplied from the liquid storage section to the reacting section 2.

Actually, 4 mL of an acid solution was accommodated in the liquidstorage section 1 and 1 g of sodium boron hydride was accommodated inthe reacting section 2, and the fuel cell was driven. Then, a volume ofsupply of the acid solution to the reacting section 2 was automaticallyadjusted, and the generation of electric power was continued until allthe acid solution in the liquid storage section 1 was moved to thereacting section 2. In this case, the period of time of electric powergeneration was 10.6 hours at the constant current 0.5 A, and theelectric current generating efficiency with respect to the theoreticalvalue was 94%. Due to the foregoing, the following was made clear. Bythis structure, a volume of supply of the reacting solution isautomatically controlled according to the output of the fuel cell, andthe reacting solution can be highly effectively used for generatingelectric power.

Embodiment 7

FIG. 8 is an arrangement view showing a case in which a movable wall isused for the pressure adjusting device of the liquid storage section ofthe fuel cell system of the present invention. The constitution andfunction of the liquid storage section 1, the reacting section 2, thegas storage section 3 and the fuel cell are the same as those ofEmbodiment 1.

In this embodiment, the pressure adjusting device is the second movablewall 22 which is composed of an elastic body and attached to the liquidstorage section 1. When the reacting solution is moved from the liquidstorage section 1 to the reacting section 2, the inner pressure in theliquid storage section 1 is lowered. Therefore, a differential pressureis generated between the atmospheric pressure and the inner pressure inthe liquid storage section 1. Accordingly, the second movable wall 22 isdeflected by the differential pressure to the side on which a volume ofthe liquid storage section 1 can be decreased. Due to the foregoing, theinner pressure in the liquid storage section 1 can be maintained at theatmospheric pressure.

Embodiment 8

FIG. 9 is an arrangement view showing a case in which a magnet is usedfor the pressure adjusting device of the liquid storage section of thefuel cell system of the present invention. The constitution and functionof the liquid storage section 1, the reacting section 2, the gas storagesection 3 and the fuel cell are the same as those of Embodiment 1.

In this embodiment, the pressure adjusting device is composed in such amanner that the second movable wall 22 attached to the liquid storagesection 1 is moved by a magnet. The detail are described below. First,the magnet 23 a is arranged on a face of the second movable wall 22opposing to the liquid storage section 1. The magnet 23 b is arranged ina stationary portion opposing to the magnet 23 a. Therefore, the magnets23 a and 23 b repulse each other. As a result, although the innerpressure in the liquid storage section 1 is lowered when the reactingsolution is moved from the liquid storage section 1 to the reactingsection 2, the second movable wall 22 is given a repulsion forcegenerated by the magnets 23 a, 23 b. Therefore, the second movable wall22 is moved to the side on which the volume of the liquid storagesection 1 can be reduced. Due to the foregoing, the inner pressure inthe liquid storage section 1 can be maintained to be the same as themagnetic repulsion force.

According to this structure, electric power was generated by the fuelcell while the magnetic repulsion condition was made to be the same asthe condition of Embodiment 1. The result of this embodiment was thesame as the result of Embodiment 1. Accordingly, it was confirmed thatthe magnet was effectively used for the pressure adjusting device.

Embodiment 9

FIG. 10 is an arrangement view showing a case in which a motor is usedfor the pressure adjusting device of the liquid storage section of thefuel cell system of the present invention. The constitution and functionof the liquid storage section 1, the reacting section 2, the gas storagesection 3 and the fuel cell are the same as those of Embodiment 1.

In this embodiment, the pressure adjusting device was the second movablewall 22 which was attached to the liquid storage section 1 and moved bya motor. To be in more detail, first, the motor 24 was arranged in astationary portion in the periphery of the second movable wall 22. Theslider 26 was attached to the second movable wall 22. A rotary motion ofthe motor 24 was converted into a linear motion by the slider 26, sothat the second movable wall 22 could be pushed and the inner pressurein the liquid storage section 1 could be increased.

Embodiment 10

FIG. 11 is an arrangement view showing a case in which a spring is usedfor the pressure adjusting device of the liquid storage section of thefuel cell system of the present invention. The constitution and functionof the liquid storage section 1, the reacting section 2, the gas storagesection 3 and the fuel cell are the same as those of Embodiment 1.

In this embodiment, the pressure adjusting device was the second movablewall 22 which was attached to the liquid storage section 1 and pushed bya spring. To be in more detail, first, one end portion of the spring 25is arranged on the face of the second movable wall 22 opposing to theliquid storage section 1. The other end portion of the spring 25 isarranged in a stationary portion located at a position opposing to this.Due to this structure, the second movable wall 22 is pushed by thespring 25. As a result, although the inner pressure in the liquidstorage section 1 is lowered when the reacting solution is moved fromthe liquid storage section 1 to the reacting section 2, the secondmovable wall 22 is given a force by the spring 25 and moved to the sideon which a volume of the liquid storage section 1 can be reduced. Due tothe foregoing, the inner pressure in the liquid storage section 1 can bemaintained at the same pressure as that of the spring load.

In this case in which the spring 25 is used, according to the Hooke'slaw, the deflection and the pushing force are correlated to each other.Therefore, it is difficult to obtain a constant pushing force. However,as long as all the movement of the second movable wall 22 is in a rangein which the Hooke's law can be applied, the spring 25 can sufficientlyexhibit its function. In this embodiment, electric power was generatedby the fuel cell under the same reacting condition as that ofEmbodiment 1. The result of this embodiment was the same as that ofEmbodiment 1. Therefore, it was confirmed that the spring waseffectively used as the pressure adjusting device.

Embodiment 11

FIG. 12 is an arrangement view showing a case in which a gas passage isused for the pressure adjusting device of the liquid storage section ofthe fuel cell system of the present invention. The constitution andfunction of the liquid storage section 1, the reacting section 2, thegas storage section 3 and the fuel cell are the same as those ofEmbodiment 1.

In this embodiment, the gas passage 30 was provided so that hydrogencould be moved from the reacting section 2 to the liquid storage section1. The pressure reducing device 31 was arranged in the gas passage 30 sothat the pressure of hydrogen moving to the liquid storage section 1could be adjusted at 0.1 MPa. The action of this device will beexplained below. In this case, an aqueous solution of methanol 30 wt %was used as the reacting solution. Although not shown in the drawing, inthe reacting section 2, a copper catalyst and a heater for vaporizingthe aqueous solution of methanol were attached to a passage in which theaqueous solution of methanol flowed.

First, the aqueous solution of methanol was supplied to the reactingsection 2 and hydrogen was generated. At this time, the pressure in thereacting section 2 was raised. On the contrary, the inner pressure inthe liquid storage section 1 was reduced due to the movement of theaqueous solution of methanol. Therefore, hydrogen was supplied from thereacting section 2 to the liquid storage section 1 through the gaspassage 30 to suppress a reduction in the pressure in the liquid storagesection 1. Since the pressure reducing device 31 is arranged in the gaspassage 30, the supply of hydrogen to the liquid storage section 1 stopswhen the inner pressure in the liquid storage section 1 reached 0.1 MPa.

Next, when hydrogen was consumed by the fuel cell and the inner pressurein the reacting section 2 was decreased to a value lower then 0.1 MPa,the aqueous solution of methanol was supplied to the reacting section 2through the liquid supply passage 13. After that, the above operationwas repeatedly conducted. It was confirmed that a volume of supply ofthe reacting solution was automatically controlled in this structure andthe fuel cell was continuously operated as described above.

Embodiment 12

FIG. 13 is an arrangement view showing a case in which a gas passage isused for the pressure adjusting device of the liquid storage section ofthe fuel cell system of the present invention. The constitution andfunction of the liquid storage section 1, the reacting section 2, thegas storage section 3 and the fuel cell are the same as those ofEmbodiment 1.

In this embodiment, the liquid passage between the liquid storagesection 1 and the reacting section 2 was composed of a liquidtransmitting film 32 a, and the gas passage 30 was composed of a gastransmitting film 32 b. Since a pressure loss caused by the gastransmitting film 32 b was big, the gas transmitting film 32 bfunctioned in the same manner as the pressure reducing device 31 ofEmbodiment 11. Therefore, it was confirmed that the same effect as thatof Embodiment 11 was provided by this structure.

Embodiment 13

FIGS. 14( a) and 14(b) are arrangement views showing a case in which avolume of the reacting solution is controlled by a change in thepressure in the gas storage section of the fuel cell system of thepresent invention. FIG. 14( a) is a view showing a state in which thereacting solution movement is stopped, and FIG. 14( b) is a view showinga state in which the reacting solution is moved to the reacting section.The liquid storage section 1 is a portion in which the reacting solutionfor generating hydrogen is stored. After the reacting solution has beentemporarily accommodated in the accommodating section 33, it is suppliedto the reacting section 2. The reacting portion 2 is provided with areactant capable of generating hydrogen when the reactant comes intocontact with the reacting solution. Therefore, when the reactingsolution is supplied to the reacting section 2, hydrogen is generated inthe reacting section 2. The thus generated hydrogen is supplied to thegas storage section 3. The gas storage section 3 is a portion in whichthe hydrogen supplied from the reacting section 2 is temporarily stored.The fuel cell includes an anode 4 a, a solid high molecular electrolytefilm 4 b and a cathode 4 c. Hydrogen in the gas storage section 3 iselectrochemically oxidized by the anode 4 a and electricity isgenerated.

This embodiment includes an accommodating section moving mechanism formoving the accommodating section 33. The accommodating section movingmechanism was composed of a third movable wall 34. One face of the thirdmovable wall 34 was pushed by the pressure of the gas storage section 3,and the other face of the third movable wall 34 was pushed by thepressurizing means 35. In this embodiment, the pressurizing means 35 wascomposed a spring. In order to link the third movable wall 34 with theaccommodating section 33, the connecting section 36 was attached to boththe third movable wall 34 and the accommodating section 33. Further, inthis case, when the third movable wall 34 was moved in a cylindricalcontainer, hydrogen was prevented from leaking out from the gas storagesection 3.

In order to facilitate a movement of the reacting solution into thereacting section 2, the porous member 37 was arranged in a portion towhich the opening portion 38 of the accommodating section 33 in thereacting section 2 was open. The porous member 37 sucks up the reactingsolution from the accommodating section 33 by the capillary phenomenon.

Next, the action of the mechanism of moving the reacting solution willbe explained below. First, in the case where a sufficiently large volumeof hydrogen exists in the gas storage section 3 and the inner pressureis high, the third movable wall 34 is pushed onto the pressurizing means35 side, and the position of the opening portion 38 of the accommodatingsection 33 coincides with the liquid storage section 1 by the action ofthe connecting section 36 corresponding to the position of the thirdwall 34. The shut-off section 39 a shuts off the accommodating section33 from the reacting section 2. Accordingly, the reacting solutionenters the accommodating section 33 and is accommodated.

Next, when hydrogen is consumed by the anode 4 a of the fuel cell andthe inner pressure in the gas storage section 3 is decreased to a valuelower than the pressure given by the pressurizing means 35, the thirdmovable wall 34 is pushed to the gas storage section 3 side.Accordingly, the accommodating section 33 is moved by the action of theconnecting section 36, and the position of the opening portion 38 agreeswith the reacting section 2. The shut-off section 39 b shuts off theaccommodating section 33 from the liquid storage section 1. Due to theforegoing, first, the reacting solution in the accommodating section 33soaks into the porous member 37 in the reacting section 2. Therefore,the reacting solution can be moved from the accommodating section 33into the reacting section 2.

In this embodiment, an aqueous solution of sodium hydride was used asthe reacting solution, and zinc particulates were provided in thereacting section. Although not shown in the drawing, since both reactintensely to each other, a hydrogen transmitting film was arrangedbetween the reacting section 2 and the gas storage section 3 so that thereacting product could not be moved to the gas storage section 3. Sincethe hydrogen transmitting film was arranged between the reacting section2 and the gas storage section 3, the inner pressure respondingproperties of the reacting section 2 and the gas storage section 3 werenot good. However, in the case where hydrogen in the gas storage section2 was consumed and the inner pressure was lowered, the accommodatingsection 33 was moved being linked with the third bulkhead 34 and anaqueous solution of sodium hydroxide was supplied to the reactingsection 2. As a result, hydrogen was generated in the reacting section2, and it was confirmed that the hydrogen pressure was raised in the gasstorage section 3 and the fuel cell was continuously operated.

Embodiment 14

FIGS. 15( a) and 15(b) are arrangement views showing a case in which avolume of the reacting solution is controlled by a change in thepressure in the gas storage section of the fuel cell system of thepresent invention. FIG. 15( a) is a view showing a state in which thereacting solution movement is stopped, and FIG. 15( b) is a view showing astate in which the reacting solution is moved to the reacting section.The constitution and function of the liquid storage section 1, thereacting section 2, the gas storage section 3 and the electric powergenerating section are the same as those of Embodiment 13. In thisconnection, in this embodiment, the third movable wall 34 is moved in acylinder connecting the liquid storage section 1 with the gas storagesection 3. The third movable wall 34 and the accommodating section 33are integrated with each other into one body.

The accommodating section 33 has an opening portion 38. A position ofthe opening portion 38 coincides with the liquid storage section 1 orthe reacting section 2, and the reacting solution is sent to or receivedfrom these two portions through the opening portion 38. To be in moredetail, when the inner pressure in the gas storage section 3 is higherthan the inner pressure in the liquid storage section 1, the thirdmovable wall 34 and the accommodating section 33 are pushed to theliquid storage section 1 side, and the position of the opening portion38 coincides with the liquid storage section 1. The shut-off section 39a shuts off the accommodating section 33 from the reacting section 2.Accordingly, the reacting solution is accommodated in the accommodatingsection 33. On the other hand, when hydrogen is consumed and the innerpressure in the gas storage section 3 is decreased to a value lower thanthe inner pressure in the liquid storage section 1, the third movablewall 34 is moved to the gas storage section 3 side. Accordingly, theaccommodating section 33 is shut off from the liquid storage section 1by the shut-off section 39 b, and the reacting section 2 and the openingportion 38 face each other. In the reacting section 2, the porous member37 for facilitating a movement of the reacting solution is arranged.Accordingly, it becomes possible to move the reacting solution from theaccommodating section 33 to the reacting section 2.

In this embodiment, in the same manner as that of Embodiment 13, it wasevaluated by using an aqueous solution of sodium hydroxide and zincwhether or not the reacting solution could be continuously moved and thefuel cell could be continuously operated. As a result, it was confirmedthat the reacting solution was automatically moved and the fuel cell wascontinuously operated.

Embodiment 15

FIG. 16 is an arrangement view showing a case in which a volume ofgeneration of the reacting gas is controlled when an area of thereacting portion of the fuel cell system is made to be variable. FIG.16( a) is a view showing a state in which the reaction of generatinghydrogen is stopped, and FIG. 16( b) is a view showing a state in whichhydrogen is generated. The fuel cell includes an anode 4 a, a solid highmolecular electrolyte film 4 b and a cathode 4 c. Hydrogen accommodatedin the gas storage section 3 is electrochemically oxidized by the anode4 a so that electric power can be generated. The liquid storage section1 is a portion for storing the reacting solution to generate hydrogen.The gas storage section 3 is a portion for temporarily storing hydrogenso that the stored hydrogen can be sent to the anode 4 a. The reactingmember 40 is arranged on a bottom face of the liquid storage section 1.When the reacting member 40 comes into contact with there actingsolution, hydrogen is generated. In order to make a contact area of thereacting solution with the reacting member 40 variable, the movablebulkhead 41 is arranged in an upper portion of the reacting member 40.The bulkhead 41 is provided with a through-hole 43 so that the reactingmember 40 and the reacting solution can be contacted with each other soas to generate hydrogen. Further, the connecting pipe 42 is arrangedwhich is used for supplying hydrogen, which is generated in the liquidstorage section 1, to the gas storage section 3.

The bulkhead 41 is slid by a differential pressure between the pressurein the gas storage section 3 and the pressure in the pressurizing device44. That is, when a sufficiently large volume of hydrogen exists in thegas storage section 3 and the inner pressure is high, the through-hole43 of the bulkhead 41 is located at the position where it is notcontacted with the reacting member 40. However, when hydrogen in the gasstorage section 3 is consumed and the inner pressure in the gas storagesection 3 is decreased to a value lower then the pressure of thepressurizing device 44, the bulkhead 41 is moved and the position of thethrough-hole 43 overlaps the reacting member 40, and the reactingsolution is supplied to the reacting member 40 through the through-hole43 and hydrogen is generated.

In this embodiment, magnesium was used for the reacting member 40, andan aqueous solution of sulfuric acid was used for the reacting solution.It was confirmed that the position of the reacting member 40 was changedaccording to the output of the fuel cell and the hydrogen generatingreaction and that the advance and stoppage of the hydrogen generatingreaction were automatically repeated.

Embodiment 16

FIG. 17 is an arrangement view showing a case in which a volume ofgeneration of the reacting gas is controlled when an area of thereacting portion of the fuel cell system is made to be variable. FIG.17( a) is a view showing a state in which the reaction of generatinghydrogen is stopped, and FIG. 17( b) is a view showing a state in whichhydrogen is generated. The constitution and function of the liquidstorage section 1, the reacting section 2, the gas storage section 3 andthe electric power generating section are the same as those ofEmbodiment 15. In this connection, in this embodiment, the bulkhead 41is a stationary member, and the reacting member 40 is moved. In portionsof the reacting member 40 coming into contact with the pressurizingmember 44 and the gas storage member 3, the non-reacting member 45,which causes no reaction, is provided. In the same manner as that ofEmbodiment 15, in the case where the reacting member 40 moves and theposition of the reacting member 40 coincides with the position of thethrough-hole 43, hydrogen can be generated. The reacting member 40 ismoved by the pressure of hydrogen in the gas storage section 3.Therefore, this movement of the reacting member 40 corresponds to thestate of operation of the fuel cell.

In this embodiment, an aqueous solution of sodium boron hydride was usedfor the reacting solution, and nickel mesh, which bore a rutheniumcatalyst, was used for the reacting member 40. It was confirmed that theposition of the reacting member 40 was changed according to the outputof the fuel cell and the hydrogen generation and that the advance andstoppage of the hydrogen generating reaction was automatically repeated.

Embodiment 17

FIG. 18 is an arrangement view showing a case in which a gas storagetank of the fuel cell system of the present invention is used. Hydrogenis sent from the storage tank 50 to the gas storage section 3 whenhydrogen passes in the gas pipe 52 connected to the storage tank 50 andfurther hydrogen passes in the pressure reducing means 51. After that,the hydrogen is once stored in the gas storage section 3 and then sentto the anode 4 a of the fuel cell and used for generating electricpower. At this time, the hydrogen is used only for the fuel cellreaction and the hydrogen is not leaked outside the fuel cell system.Accordingly, the inner pressure in the gas storage section 3 is a factordetermined by the hydrogen consumption by the fuel cell and the hydrogensupply from the pressure reducing means 51.

Specifically, a regulator was used for the pressure reducing means 51,and the pressure of hydrogen to be outputted was adjusted at 0.1 MPa.When the inner pressure in the gas storage section 3 was decreased to avalue lower than 0.1 MPa by the operation of the fuel cell, hydrogen wassupplied by the action of the regulator and the pressure was adjusted at0.1 MPa. Due to the foregoing, it was made clear that the condition ofstably operating the fuel cell by automatically adjusting the hydrogenpressure without consuming electric power was created.

As explained above, according to the fuel cell of the present invention,a volume of supply of the reacting solution can be controlled inaccordance with a state of driving the fuel cell without directlydetecting an output of electric power of the fuel cell. Therefore, itbecomes unnecessary to provide electronic parts and conduct electricalprocessing relating to control. Accordingly, the energy consumption canbe reduced. When the number of parts is decreased, the fuel cell can bereduced in weight. At the same time, the manufacturing cost can bereduced.

1. A fuel cell system comprising: a liquid storage section for storing areacting solution; a reacting section for generating reacting gas fromthe reacting solution supplied from the liquid storage section; a gasstorage section for storing the reacting gas supplied from the reactingsection; a fuel cell for generating electricity while the reacting gassupplied from the gas storage section is being used as fuel, the fuelcell having an electrode connected to a solid high molecular electrolytefilm; means for supplying the reacting solution from the liquid storagesection to the reacting section when the pressure in the liquid storagesection is higher than the pressure in the reacting section and forstopping the supply of the reacting solution when the pressure in theliquid storage section is lower than the pressure in the reactingsection; and a pressure adjusting device that suppresses a reduction inthe pressure in the liquid storage section caused when the reactingsolution is supplied from the liquid storage section to the reactingsection, the pressure adjusting device having a port through which airat atmospheric pressure is supplied into the liquid storage section, anda check valve for obstructing backward flow of the air from the liquidstorage section through the port.
 2. A fuel cell system according toclaim 1; wherein the means comprises a check device for preventing flowof substances from the reacting section to the liquid storage section,the check device being disposed in a liquid supply passage that suppliesthe reacting solution from the liquid storage section to the reactingsection.
 3. A fuel cell system according to claim 2; wherein the checkdevice opens and closes the liquid supply passage.
 4. A fuel cell systemaccording to claim 2; wherein the check device comprises a check valvefor preventing flow of substances from the reacting section to theliquid storage section.
 5. A fuel cell system according to claim 2;wherein the check device comprises a movable wall disposed in the liquidsupply passage between the liquid storage section and the reactingsection; and wherein when the pressure in the reacting section is raisedby generation of the reacting gas, the movable wall is moved by a forcegenerated by the pressure in the reacting section in a direction so asto close the liquid supply passage; and wherein when the pressure in thereacting section is lowered by the consumption of the reacting gas, themovable wall is moved in a direction so as to open the liquid supplypassage.
 6. A fuel cell system according to claim 1; wherein thepressure adjusting device has a fan for supplying air from an exteriorof the fuel cell.
 7. A fuel cell system comprising: a liquid storagesection that stores a reacting solution; a reaction section thatgenerates reacting gas from the reacting solution supplied from theliquid storage section; a gas storage section that stores the reactinggas supplied from the reaction section; a fuel cell that generateselectricity using the reacting gas supplied from the gas storage sectionas fuel; means for supplying the reacting solution from the liquidstorage section to the reaction section when the pressure in the liquidstorage section is higher than the pressure in the reaction section andfor stopping the supply of the reacting solution when the pressure inthe liquid storage section is lower than the pressure in the reactionsection; and a pressure adjusting device that repeatedly admits air atatmospheric pressure into the liquid storage section whenever thepressure in the liquid storage section is lower than atmosphericpressure thereby suppressing a reduction in pressure in the liquidstorage section occurring when the reacting solution is supplied fromthe liquid storage section to the reaction section.
 8. A fuel cellsystem according to claim 7; wherein the fuel cell comprises a solidpolymer membrane fuel cell having a solid polymer electrolyte membranesandwiched between electrodes.
 9. A fuel cell system according to claim7; wherein the means includes a check device that permits flow of thereacting solution through a liquid supply path from the liquid storagesection to the reaction section and that prevents flow of substancesthrough the liquid supply passage from the reaction section to theliquid storage section.
 10. A fuel cell system according to claim 9;wherein the check device comprises a check valve.
 11. A fuel cell systemaccording to claim 9; wherein the check device comprises a movable wallmovable to open and close the liquid supply passage, and apressure-responsive member movable in response to a pressuredifferential between the pressure in the liquid storage section and thepressure in the reaction section to move the movable wall.
 12. A fuelcell system according to claim 11; wherein the pressure-responsivemember comprises a piston.
 13. A fuel cell system comprising: a liquidstorage section for storing a reacting solution; a reacting section forgenerating reacting gas from the reacting solution supplied from theliquid storage section; a gas storage section for storing the reactinggas supplied from the reacting section; a fuel cell for generatingelectricity while the reacting gas supplied from the gas storage sectionis being used as fuel, the fuel cell having an electrode connected to asolid high molecular electrolyte film; means for supplying the reactingsolution from the liquid storage section to the reacting section whenthe pressure in the liquid storage section is higher than the pressurein the reacting section and for stopping the supply of the reactingsolution when the pressure in the liquid storage section is lower thanthe pressure in the reacting section; and a pressure adjusting deviceconfigured to suppress a reduction in the pressure in the liquid storagesection caused when the reacting solution is supplied from the liquidstorage section to the reacting section, the pressure adjusting devicecomprising a movable wall of the liquid storage section that undergoesmovement to adjust the pressure in the liquid storage section by a forcefrom atmospheric pressure, a driving force of a motor, a magnetic force,or a force generated by a spring.
 14. A fuel cell system according toclaim 13; wherein an exterior surface of the movable wall communicateswith the atmosphere so that atmospheric pressure applies the force tothe movable wall.
 15. A fuel cell system according to claim 14; whereinthe movable wall comprises an elastic body.
 16. A fuel cell systemcomprising; a liquid storage section for storing a reacting solution; areacting section for generating reacting gas from the reacting solutionsupplied from the liquid storage section; a gas storage section forstoring the reacting gas supplied from the reacting section; a fuel cellfor generating electricity while the reacting gas supplied from the gasstorage section is being used as fuel, the fuel cell having an electrodeconnected to an electrolyte film; means for supplying the reactingsolution from the liquid storage section to the reacting section whenthe pressure in the liquid storage section is higher than the pressurein the reacting section and for stopping the supply of the reactingsolution when the pressure in the liquid storage section is lower thanthe pressure in the reacting section; and a pressure adjusting devicethat suppresses a reduction in the pressure in the liquid storagesection caused when the reacting solution is supplied from the liquidstorage section to the reacting section, the pressure adjusting devicecomprising a gas passage through which the reacting gas flows from thereacting section to the liquid storage section, and a pressure reducingdevice disposed in the gas passage for reducing to a preselectedpressure the pressure of the reacting gas flowing from the reactingsection to the liquid storage section.
 17. A fuel cell system accordingto claim 16; wherein the means includes a check device that permits flowof the reacting solution through a liquid supply path from the liquidstorage section to the reacting section and that prevents flow ofsubstances through the liquid supply passage from the reacting sectionto the liquid storage section.
 18. A fuel cell system according to claim16; further comprising a liquid supply passage through which thereacting solution is supplied from the liquid storage section to thereacting section, the diameter of the liquid supply passage being largerthan the diameter of the gas passage.
 19. A fuel cell system accordingto claim 16; wherein the liquid supply passage is hydrophilic.
 20. Afuel cell system according to claim 16; wherein the gas passage ishydrophobic.
 21. A fuel cell system according to claim 16; wherein eachof the liquid supply passage and the gas passage is formed of one of afilm or a porous member through which liquid or gas is transmitted. 22.A fuel cell system according to claim 17; wherein the check devicecomprises a check valve.
 23. A fuel cell system according to claim 7;wherein the pressure adjusting device comprises an intake passage thatcommunicates at one end with air at atmospheric pressure and at theother end with the liquid storage section, and a check valve disposed inthe intake passage for admitting air into the liquid storage section andpreventing backflow of air from the liquid storage section.
 24. A fuelcell system according to claim 23; wherein the means includes a checkdevice that permits flow of the reacting solution through a liquidsupply path from the liquid storage section to the reaction section andthat prevents flow of substances through the liquid supply passage fromthe reaction section to the liquid storage section.
 25. A fuel cellsystem according to claim 24; wherein the check device comprises a checkvalve.
 26. A fuel cell system according to claim 24; wherein the checkdevice comprises a movable wall movable to open and close the liquidsupply passage, and a pressure-responsive member movable in response toa pressure differential between the pressure in the liquid storagesection and the pressure in the reaction section to move the movablewall.
 27. A fuel cell system according to claim 26; wherein thepressure-responsive member comprises a piston.